The present invention relates to a method of an apparatus for determining the load carried by large trucks. Such trucks are commonly used in open pit mining.
Truck loading systems have been used in the past for trucks which carry very heavy loads. Such systems are used to determine the load being carried so that the trucks are not overloaded and so that the amount of material being moved by a fleet of such trucks is known.
U.S. Pat. No. 4,831,539 discloses a method and apparatus for a complete system which provides communication from the trucks and a central station so that there is a continuing and complete record of the material loaded and moved by the trucks and the location to which the material was taken and dumped. The weighing apparatus includes fluid filled tubing which is substituted for the cushioning support materials added along the length of the parallel beams of the frame. The fluid filled tubing combined with pressure sensors provides the desired weight indication of the load carried by the truck.
U.S. Pat. No. 4,839,835 discloses a similar fluid filled tubing between the beams and the frame to coact with pressure sensors to provide the desired weight. This patent contains a discussion of the prior attempts at load weighing and the problems encountered by the pivotal connection between the frame and the truck bed and the disadvantages of the concentration of the load on the frame by the use of load sensors which are incorporated into the hinge assemblies and the hydraulic. One of these problems is recited to be, the structural integrity of the truck may be degraded by modifications of the hinge assemblies and hydraulic cylinders required to incorporate the loads sensors.
Load measurements on front end loaders have been made by measuring the pressure in the hydraulic cylinders used to carry the load for the structure. In such case the hydraulic cylinders reflect the total load carried and not just a portion of the load as is the case in the usual tilting bed truck.